The present invention is directed to bis-(alkoxy)tetrathiotricarboxylates as well as herbicidal compositions containing these compounds and the use of these compounds as post-emergence herbicides.
It has been predicted that the reaction of potassium ethylxanthate and phosgene would produce bis(ethoxy)tetrathiotricarboxylate. It is reported in Willcox, (1906) J. Amer. Chem. Soc. 28:1031-1034, however, that the expected product was not obtained, the reaction being "complex" in nature. Zhuravlev and Galchenko, (1947) Zhurnal Prikladnoi Khimii, pp. 1038-1043 report that the reaction produces xanthogenic thioanhydride, potassium chloride, and carbonyl sulfide. There appears to be a suggestion in the paper that the tetrathiotricarboxylate is an unstable intermediate in the reaction. There is no evidence reported, however, indicating that the tetrathiotricarboxylate was formed.
The preparation of dialkyltricarbonates and corresponding dialkyl dithioltricarbonates is known in the art. For examples, Friederang and Tarbell, (1968) Tetrahedron Letters 55:5535-5536, discloses the synthesis of di-t-butyl dithioltricarbonate from the reaction of sodium t-butyl thiolcarbonate and phosgene. Dean and Tarbell, Chemical Communications 1969:728-729, discloses the preparation of di-t-butyl tricarbonate as well as di-isopropyl dithioltricarbonate and di-isopropyl tricarbonate. The isopropyl compounds, however, could not be obtained in pure form because they decomposed to their corresponding dicarbonates.
The reaction products of dialkyl tricarbonates and dialkyl dithiotricarbonates with alcohols, mercaptans, primary amines and secondary amines have also been reported. The reaction of the di-ty-butyl compounds with alcohols and mercaptans yields mixed dicarbonates, reaction with primary amines yields isocyanates via a carbonic carbamic anhydride intermediate, and reaction with secondary amines yields carbamic anhydrides. See Dean and Tarbell, (1971) J. Org. Chem. 36:1180-1183.